68kMLA Classic Interface

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Is the Quadra 610 Quaddoubler supposed to work in an LC475?

Posted by: Bolle on 2026-03-13 08:01:04 I received the card yesterday and dived right into it. Mapped out the schematics and found a broken connection on a data line that should obviously have been connected. After looking around I quickly found a suspiciously looking trace. I have yet to repair and test the card but I'm certain it's going to work afterwards. It looks like one pin got lost while moving the card around between Macs so I have to replace that one too. What kept me distracted from repairing the card in the first place was drawing coloured lines 😅 24 hour turnaround reverse engineering right there. The GAL20RA10 has also been cracked but not yet verified because I don't have any of that type around. Looks like sourcing them is not going to be too easy. Will keep everyone updated.

Posted by: Bolle on 2026-03-13 08:55:56 One small patch wire later and swapped the broken pin with another one that's unused... And it's fixed. To totally not answer the initial question if the Q610 variant would work in the LC475 or not I gave it a quick spin in my Q700 because it has been sitting in my office anyways. While it blocks the Nubus slots it just humming along nicely.

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